sample3.cpp

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/*
Copyright(c) 2002-2005 Anatoliy Kuznetsov(anatoliy_kuznetsov at yahoo.com)

Permission is hereby granted, free of charge, to any person 
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and to permit persons to whom the Software is furnished to do so, 
subject to the following conditions:

The above copyright notice and this permission notice shall be included 
in all copies or substantial portions of the Software.

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*/

/** \example sample3.cpp
 Exmaple demonstrates using bitvectors with different initial
 block allocation strategy. 
 Bitvector 1 (bv1) by default working without RLE compression option
 (best performance, maximum memory consumption). 
 Bitvector 2 (bv2) will be working in compression mode and use less memory.
 
  \sa bm::bvector<>::set_new_blocks_strat() 

  For more information please visit: http://bmagic.sourceforge.net

*/

#include <stdlib.h>
#include <iostream>
#include "bm.h"

using namespace std;

const unsigned MAX_VALUE = 1000000;

// This procedure creates very dense bitvectors.
// The resulting set will consists mostly from ON (1) bits
// interrupted with small gaps of 0 bits.

void fill_bvector(bm::bvector<>* bv1, bm::bvector<>* bv2)
{
    for (unsigned i = 0; i < MAX_VALUE; ++i)
    {
        if (rand() % 2500)
        {
            bv1->set_bit(i);
            bv2->set_bit(i);
        }
    }
}


void print_statistics(const bm::bvector<>& bv)
{
    bm::bvector<>::statistics st;
    bv.calc_stat(&st);

    cout << "Bits count:" << bv.count() << endl;
    cout << "Bit blocks:" << st.bit_blocks << endl;
    cout << "GAP blocks:" << st.gap_blocks << endl;
    cout << "Memory used:"<< st.memory_used << endl;
    cout << "Max.serialize mem.:" << st.max_serialize_mem << endl << endl;;
}


int main(void)
{
    bm::bvector<>   bv1;    
    bm::bvector<>   bv2;

    bv2.set_new_blocks_strat(bm::BM_GAP);  //  set DGAP compression mode ON

    fill_bvector(&bv1, &bv2);  // Fill both bvectors with the same values

    // For a given distrubution statistics should demonstrate
    // lower memory consumption for the vector with compression

    print_statistics(bv1);    
    print_statistics(bv2);

    // Now run optimization procedure for bv1 and see statistics.

    bv1.optimize();

    print_statistics(bv1);    

    return 0;
}

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